Carbonates containing halogenated neopentyl groups

ABSTRACT

New halogenated aliphatic carbonates containing halogenated neopentyl groups have been found which are extremely useful as fire retardant additives for polyesters.

United States Patent Exner et al. Aug. 29, 1972 [54] CARBONATES CONTAINING [56] 7 References Cited HALOGENATED NEOPENTYL GROUPS UNITED STATES PATENTS 72 I t H. E E R. L

[ 1 figf 'g fil f g 3,382,207 5/1968 Jaqwiss ..260/45.7

all ofMidland 48640 3,542,740 11/1970 Pumpelly et al. ..260/77.5 [73] Assignee: ilhel ligtvhChemical Company, Mid- Primary Examiner Lewis Gotts I an Assistant ExaminerDiana G. Rivers Flled! 1970 Attorney-Griswold & Burdick, Herbert D. Knudsen 7211 Appl. No.: 60,778 and Rehberg [57] ABSTRACT [52] US. Cl ..260/463, 260/457 R, 260/4595 51 m CL "1307c 69/00 C08 51/58, cog 39/02 New halogenated aliphatic carbonates containing 5 halogenated neopentyl groups have been found which Field of Search ..260/463, 77.5 D, 47 XA are extremely useful as fire retardant additives for polyesters.

7 Claims, N0 Drawings CARBONATES CONTAINING HALOGENATED NEOPENTYL GROUPS BACKGROUND OF THE INVENTION Considerable research has been done to find a suitable fire retardant for polyesters, especially polyester fiber. Finding a suitable fire retardant has been difficult because of the high temperatures involved in processing polyesters. Such temperatures usually range from about 290 to about 300C. Normal fire retardant additives degrade at such temperatures to cause color forming impurities which adversely affect the commercial desirability of the end product.

Decabromodiphenyl oxide and octabromobiphenyl have been found to be suitable fire retardants for polyester fibers, but the large amount of fire retardant necessary to make the polyester self-extinguishing deleteriously affects the physical integrity of the polyester. Furthermore, the light sensitivity of the halogenated aromatic compounds causes them to degrade. The resulting color upon extended exposure to light decreases their commercial desirability.

SUMMARY OF THE INVENTION It has now been found according to the present invention that halogenated aliphatic carbonates having the general formula X is independently Br or Cl, and

n is an integer of to are suitable and effective fire retardant additives for polyesters, especially polyethylene terephthalate. In the process of preparing the fire retardant polyester, the fire retardant agent of the invention is incorporated physically into a melt of the polyester and the polyester containing the fire retardant is processed to give the desired product.

Thus, the invention comprises the new compounds which have been found to be especially effective fire retardants for polyesters, a method for making polyester fire retardant, and the final composition of the polyester containing the fire retardant compound.

The compounds may be prepared by the well-known carbonate reaction where a monoor dihydric alcohol is reacted with phosgene to form a carbonate ester. For

the fire retardant additives of the invention, phosgeneor a chloroformate is reacted with a trihaloneopentyl alcohol, dihaloneopentyl glycol or tetrahalobisphenol A in the proportions necessary to obtain the desired compound of the general formula. Such reactions are generally conducted in the presence of a base catalyst such as pyridine, sodium hydroxide or sodium carbonate, with weak bases such as pyridine being preferred. Normal room temperature may suitably be employed to obtain the desired reaction and pressure may be applied as needed to maintain the liquid phase. After the reaction is completed, the product may be isolated by any conventional means of isolation such as crystallization or distillation.

The compounds of the invention may be any of those corresponding to the general formula above. In a specific preparation of a compound wherein M is dihaloneopentanediyl and n is 4, phosgene is reacted with trihaloneopentyl alcohol to form the chloroformate, then dihaloneopentyl glycol and phosgene are alternately reacted to give a molecule having 4 units of the neopentyl glycol and terminal hydroxyls. This product is then reacted with trihaloneopentyl chloroformate to give the desired compound. In like manner, tetrahalobisphenol A may be substituted for the glycol, or a mixture of tetrahalobisphenol A and dihaloneopentyl glycol may be reacted with phosgene to prepare suitable compounds of the invention. In preferred compounds, n is an integer of 0 to 5, with compounds where n is O to 2 being especially preferred.

Of special interest are:

I Compound 1 0 ll (XCHmC CHzO C 0 Q1120 (CHzX) 3 Compound 2 0 II II (XCI12)3C (EH20 C O CHzC (CHZX) QCI-IZO CO CHZC (CH2X)3 Compound 3 Also of special interest are compounds wherein each X is Br.

In the process for making the polyester fire retardant the additive of the present invention is incorporated physically into the polyester by making a melt of the polyester and then physically mixing the fire retardant additive with the polyester. The fire retardant additive is compatible and may be mechanically blended with the polyester to give a mixture of essentially homogeneous composition. The amount of additive employed in the process may vary widely but any quantity of additive imparts some fire retardant characteristics to the final product. Such amounts generally range from about 0.5 to about 10 percent by weight of halogen in the fire retardant compound based on the weight of the polyester with amounts of about 1 to about 7 percent by weight being preferred. Larger amounts of the fire retardant may be employed in the polyester, but excessive amounts tend to have a deleterious effect upon the physical integrity of the resultant polyester.

After the incorporation of the fire retardant additive, the polyester is processed in the normal manner at temperatures of about 290 to 300C. The special desirability of the fire retardants of the invention is due to the fact that they do not materially degrade to give a colored product or cause degradation of the polyester, but rather produce a clear product having fire retardant characteristics. The polyester may then be extruded into fiber or molded or shaped into any form and still maintain its desirable commercial qualities.

Example 1-Preparation of compound 1 (where X Br) In a reactor was placed 38.8 g. (0.10 mole) of 3- bromo-2,2-bis(bromomethyl)propyl chloroformate, 32.5 g. (0.10 mole) of tribromoneopentyl alcohol and 150 ml. of benzene. To this mixture was added a solution of 12.5 ml. of pyridine and 30 ml. of benzene with slight cooling over a 10 minute period. The reaction mixture was stirred at room temperature overnight and then the product was hydrolyzed by addition of 100 ml. of 5 percent hydrochloric acid. The benzene layer was washed twice with 100 ml. of water and dried over anhydrous sodium sulfate. The benzene was decanted and evaporated to yield 65 g. of light crystals which were recrystallized from carbon tetrachloride. The recrystallized material had a melting point of 109.5 to 111C. The crystals were analyzed by nuclear magnetic resonance spectroscopy and infrared analysis and found to be the desired carbonate.

Example 2Preparation of compound 2 (where X Br) In a manner similar to that described in Example 1, 38.8 g. (0.10 mole) of 3-bromo-2,2-bis- (bromomethyl)propyl chloroformate, 13.1 g. (0.05 mole) of dibromoneopentyl glycol and 250 m1. of benzene were mixed and a solution of 8 ml. of pyridine and 40 ml. of benzene was added. After the reaction mixture was stirred for 32 hours, the product was hydrolyzed with hydrochloric acid and a white solid was obtained which was recrystallized from chloroform. The crystals weighed 39.7 g. and had a melting point of 106 to l 10C.

Example 3Preparation of compound 3 (where X In the same manner as shown in example 1, 38.8 g. (0.10 mole) of 3-bromo-2,2-bis(bromomethyl)propyl chloroformate, 27.2 (0.05 mole) of tetrabromobisphenol A and 250 ml. of benzene were charged to a reactor. To this mixture 8 ml. of pyridine in 40 ml. of benzene was added and the reaction mixture was stirred overnight. After hydrolysis, washing and drying, the benzene layer was evaporated to give a solid material. The solid was dissolved in chloroform, treated with charcoal and recrystallized from benzene to give 42 g. of a white solid having a melting point of 187 to 191C. The product was identified by nuclear magnetic resonance spectroscopy as the expected compound 3.

Example 4-F ire Retardancy in Polyester Using the screening method ASTM-D2863, compounds of the invention were compared decabromodiphenyl oxide and octabromobiphenyl as fire retardant additives. In the test procedure, mixture of polyethylene terephthalate and the desired amount of fire retardant to give the indicated percentage of bromine were mixed at 250C. using a Brabender mixer. The mixture was then removed from the mill and ground to a powder. A sample was then fabricated by molding it at a pressure of 17 to 30 tons per sq. in. at 290 to 300C. on a fiberglas support. A strip of the material 4- by /r by Vs inches was cut and burned in a limiting oxygen index test (L0!) as described in Combustion and Flame, 10, 135 (1966). Compounds giving high LOI for small amounts of additive are most desirable. The results of these examinations are shown in the following table.

TABLE Comparative Fire Retardancy in Polyester Example 5Light Stability The light stability of the test samples of example 4 were examined by placing the samples 7 inches from a watt All-4 mercury vapor lamp. Samples comp. B and C containing decabromodiphenyl oxide turned yellow within 48 hours, Samples comp. D-G containing octabromobiphenyl turned yellow in 10 days, but comp. A with no additive and samples l-4 containing additives of the invention showed no discoloration even after 14 days. At these concentrations, the relative amounts appeared to have little or no affect on the light stability.

In the same manner as described in the examples above, other compounds of the invention may be prepared by reacting dibromoneopentyl glycol or tetrabromobisphenol A with phosgene to form alternating units of the glycol or tetrabromobisphenol A and phosgene and terminal chloroformate radicals and then reacting these compounds with two moles of tribromoneopentyl alcohol per mole of the compounds formed until all of the compounds have been capped.

These compounds may be incorporated into polyethylene terephthalate to give superior fire retardancy.

Also in the same manner as shown above, chlorinated neopentyl alcohol, neopentyl glycol and bisphenol A may be used to prepare a compound of the invention or chlorinated and brominated reactants containing both bromine and chlorine may be used to prepare mixed halogen compounds.

Representative examples of these compounds include:

211201 1 cmnmo onto 0 o onzc z-omo-o-o-omo (CHZBUQ o'mol (an onic 01120 c 0 CH2CCHzO c 0 OHZC 011201);

CHzCl a We claim: 1. A compound of the general formula X is independently Br or Cl, and n is an integer of 0 to 10.

XCHmGGIIZOiioomcwlnxn wherein X is independently Br or' Cl.

10 5. The compound of claim 1 of the general formula 0 O XCHmCCHZOi JOCHZO(CHZXnOHZOi 00H2C(0HX)a wherein X is independently Br or Cl.

6. The compound of claim 1 of the general formula X 1? l xoHmc 01120 c 0@- I X X 5 i c{@ 0 0 o cine (CHzX): OH; I 7 V X wherein X is independently Br or C1.

7. A compound of claim 1 wherein each X is Br. 

2. A compound of claim 1 wherein n is an integer of 0 to
 5. 3. A compound of claim 1 wherein n is an integer of 0 to
 2. 4. The compound of claim 1 of the general formula
 7. A compound of claim 1 wherein each X is Br. 